Is a Summer Trip Necessary?

As if it wasn't enough that I would be trying to deal with Jessica leaving in August for college.... Now she has decided to take a trip with her best friend for 10 days in July!  I am trying to be the big girl here and help her plan this trip, but inside, I am slowly and surely dying.  Why does her friend have to have a birthday?  I know, it is kind of irrational, but I am a mommy who is trying to avoid a mental breakdown.  I just don't know how to deal with this, but I will, I pretty much have no choice.